The present invention relates to a dumbbell with a selectable number of weight disks and comprises a base assembly, in which a first and second set of separate weight disks standing upright are insertable, the weight disks having openings which lie in alignment with one another when the weight disks stand in the base assembly, a handle with pin members axially projectable in opposing directions for insertion in the openings of the weight disks, the projection lengths of the pin members from the handle being selectable in order thereby to permit a selection of the number of weight disks accommodated on the handle, and neighbouring weight disks and the handle having mutually cooperating connecting means which are disposed, in the axial direction of the dumbbell, to interconnect neighbouring weight disks with one another and the handle, but, in a radial direction, to permit separation of one weight disk from a neighbouring weight disk and the handle, respectively.
WO 2007/123461 discloses a dumbbell which has a base unit with a handle insertable therein, the base unit having accommodation spaces for a first and second set of weight disks. The handle has pins projectable in opposing directions, which may be accommodated in central openings in the weight disks when they stand upright in the base unit.
For fixedly retaining the weight disks accommodated by the pins, the pins display, in their free ends, locking means which prevent the outermost weight disks on the pins, and thereby all weight disks located inside them, from falling off in the axial direction.
A dumbbell of this design and construction enjoys many advantages, above all in that it is extremely convenient to use, but is has proved to be somewhat fragile in terms of
pure mechanical strength. In addition, it comprises a large number of small parts, for which reason manufacturing costs are relatively high.
U.S. Pat. No. 6,416,446 also discloses a dumbbell which has a base assembly with two sets of weight plates and a handle located therebetween. The handle has rods axially extendable in opposing directions which are disposed to extend through openings in the weight plates of the dumbbell.
The weight plates according to this US patent Specification have connecting means which, in the axial direction, interconnect neighbouring weight plates but which permit separation of two adjacent weight plates in a radial direction, in practice up out of the base assembly when the dumbbell is lifted. The number of lifted weight plates is defined by the extent of the rods extendable in opposing directions outside both end surfaces of the handle.
This design and construction is complex, with gears for extending the rods, the handle having a U-shaped stirrup portion. In addition, in certain embodiments, the weight plates are interconnected pairwise via rods which are parallel with the gripping member of the handle. Both the stirrup portion and its rods can be dangerous to the wrist of the user if the handle were to be rotated in the grip of the hand.
U.S. Pat. No. 6,228,003 discloses a dumbbell which also has a handle with rods projectable in opposing directions for interconnecting the handle with an optionally selectable number of weight plates. In this construction, the weight plates or disks are united pairwise by the intermediary of rods, which are impractical on use of the dumbbell and which may constitute a risk element.
It is desirable to further develop the dumbbell intimated by way of introduction in such a manner that the drawbacks in the prior art technology are obviated. Above all, it is desirable to realise a dumbbell which is safe to use, which offers reliable fixing of the selected number of weight disks on the handle and which in addition is simple and economical in manufacture.
According to an aspect of the present invention, a dumbbell intimated by way of introduction is characterised in that the handle has locking means for locking the pin members in selected projection positions on lifting of the dumbbell out of the base assembly.